최근 수도작 재배에서 문제잡초로 부각된 다년생잡초 올방개의 방제기술을 확립하고자 경운방법(추경, 춘경, 로타리경, 경운·로타리경)에 따른 올방개발생 추이를 조사하고 이들 방법간에 차이를 보인 원인을 구명함과 동시에 이들 경운방법에서 발생된 올방개가 벼 수량에 미치는 영향을 구명하고자 하였다. 추경과 춘경한 논에서 이앙 후 40일과 50일에 발생한 올방개 발생본수는 로타리경과 경운·로타리경에 비해 적었고, 2년째 추경과 춘경의 논에서 발생한 올방개 발생본수는 1년째에 비해 적었으나 로타리경과 경운·로타리경에서는 오히려 2년째에 증가하는 경향을 보였다. 이처럼 추경과 춘경조건에서 올방개 발생수가 적었던 원인을 구명하기 위하여 괴경크기별 건조일수 경과에 따른 맹아율을 조사하였다. 괴경의 건조일수가 경과할수록 맹아율은 감소하였고, 올방개 괴경을 5일 건조시 맹아율이 5-10%로 90% 이상이 고사하였다. 흑색괴경의 올방개 맹아율은 13.3-66.7%로 평균 43.4%이었고 갈색괴경은 73.3-100%로 평균 87.3%을 보였고 괴경 크기별 맹아율에는 일정한 경향이 없었다. 포장에 올방개 괴경의 깊이를 달리하고 겨울과 봄을 보낸 후 올방개 맹아율을 조사한 결과, 괴경의 크기에 관계없이 얇게 매몰된 것이 맹아율이 낮았다. 즉 표토에 노출된 괴경은 전혀 맹아하지 않았으며 3㎝ 이내에 있는 올방개 괴경도 단지 13%의 맹아율을 보였다. 벼 초장과 분얼수의 경우 추경과 춘경간에는 차이가 없었으나 로타리경과 경운·로타리경에서는 이앙 후 40일과 60일에 추경과 춘경에 비해 감소가 뚜렷하였다. 또한 로타리경과 경운·로타리경에서 간장과 수수는 추경과 춘경에 비해 현저하게 감소하였다. 수량에서도 로타리경과 경운·로타리경이 추경에 비해 각각 17%와 11%가 감소하였다.

This research was conducted to investigate the change of pattern of Eleocharis kuroguwai Ohwi occurrence as a result of different tillage methods such as Fall plowing, Spring plowing, rotary, and plowing and rotary combined to establish controlling methods of E.kuroguwai. Since this weed has recently become more troublesome in paddy fields, the aim of this research is also to study the reason for the difference between tillage methods, and finally to investigate the effect of E. kuroguwai on the growth and yield of rice plants, and how this effect changes as a result of different tilling methods. The amount of E. kuroguwai occurring at 40 and 50 days after transplanting into paddy fields of Fall plowing and Spring plowing was less than that of rotary and plowing and rotary fields and the amount of E. kuroguwai occurring in paddy fields of Fall plowing and Spring plowing for 2 years was less than that of 1 year. However, in rotary and plowing and rotary fields, the amount of E. kuroguwai increased after 2 years. Thus, we investigated the percentage of sprouts that grew by day drying, and measured the weight of each tuber to look for the reason why lower amounts of E. kuroguwai occurred in Fall plowing and Spring plowing conditions. Sprouting percent decreased with drying period of the tuber, and when the tuber was dried for 5 days, the sprouting percent showed a 5 to 10% increase. That means over 90% died. Sprouting percent showed an average of 43.4% in black tubers and 87.3% in brown tubers, but the sprouting percent had no consistent tendency by tuber weight. When we investigated sprouting percent the year after depositing tubers in soils of different depths, the sprouting percent was lower when the tuber had been buried in shallow soil regardless of tuber weight. On the other hand, sprouting percent was 0% and 13% when the tuber was exposed on the surface and within 3 ㎝ of soil, respectively. There was no difference in plant height and number of tiller between Fall plowing and Spring plowing. However, plant height and number of tiller at 40 and 60 days after transplanting into rotary and plowing and rotary fields were lower than in the Fall plowing and Spring plowing. Also, Culm length and the number of panicle in rotary and plowing and rotary fields decreased compared with Fall plowing and Spring plowing fields. In addition, rice yield in rotary and plowing and rotary fields decreased 17% and 11% respectively compared with Fall plowing. Therefore, this research suggests that physical methods such as Fall plowing and Spring plowing coupled with chemical control methods may be useful in controlling E. kuroguwai occurring in paddy fields.